Examples of presently existing projection lighting units of the type described are illustrated in the following patents:
U.S. Pat. No. 3,314,331--E. H. Wiley, PA1 U.S. Pat. No. 3,502,864--D. M. Wagner, PA1 U.S. Pat. No. 3,761,170--L. G. Genesky et al, PA1 U.S. Pat. No. 3,789,212--D. M. Wagner.
As described therein, each unit includes a holder (or mount) and a reflector-lamp component insertable within the holder and capable of being removed in the event of repair or replacement. The lamp as used in such units is typically sealed within the reflector (see, e.g., 3,314,331) such that the lamp's pins may project from the rear of the reflector and be inserted within a suitable socket, which also forms part of the overall unit. The unit's holder is typically securedly positioned within the housing of the projector, in a manner such as illustrated in U.S. Pat. No. 3,761,170. To facilitate removal of the lamp and reflector component, an ejector (see, e.g., 3,502,864) is required to engage an outer surface of the reflector and force it in a vertical, upward direction whereupon the projector's operator can grasp the component and complete removal. One particular disadvantage of this procedure is that it necessitates forceful engagement of a glass component (the reflector) with a metal member (the ejector) which in turn can disfigure and even possibly fracture the glass article. To hopefully prevent this from occurring, manufacturers have substantially increased the reflector's wall thicknesses, thus necessitating use of greater quantities of raw material to produce this component.
Another disadvantage of projection units of the type described is that such units typically allow only vertical, downward insertion of the glass reflector and hereafter the aforedescribed vertical upward removal should repair or replacement be needed. Understandably, such restricted movement limits the versatility of these units as well as the corresponding projector housing design. The manner of insertion was believed required, however, to provide the essential, precisioned alignment of the reflector within the holder such that the assembled unit properly aligns with the remaining elements (e.g., film gate and projection lens) in the overall system. This latter alignment is understandably critical and must be maintained to assure optimum light output to the distant screen. In the particular examples illustrated in the foregoing patents, vertical insertion was also believed mandatory in order to assure proper grasping and retention of the reflector in the corresponding holder while assuring proper connection to the unit's socket. In most instances, the socket is firmly situated on an upstanding, rear segment of the holder (see, e.g., U.S. Pat. Nos. 3,502,864 and 3,789,212), or the rear portion of the reflector must be properly oriented within bifurcated prongs provided in this segment (see, e.g., U.S. Pat. No. 3,314,331). In either case, as stated, only downward placement and upward removal of the reflector, having the unit's lamp located therein, is possible.
It is believed, therefore, that a projection lighting unit which permits more than the aforedefined, restrictive singular means of insertion and removal of the unit's reflector (and lamp) within the unit's holder or mount device while still assuring precisioned alignment of the reflector within said holder would constitute a significant advancement in the projection art. It is also believed that a projection lighting unit possessing the additional features to be defined below will represent an even further art advancement.